Billings, Evelyn. <br/><br/>
Atlas of the ovulation method :  the mucus patterns of fertility and infertility / 
Evelyn L. Billings, John J. Billings and Rev. Maurice Catarinich. 
 - 3rd ed. 
 - Melbourne, Australia :  Advocate P,  1979. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Ovulation.